Sri Lanka's Upul Tharanga plays a shot during the World Cup semi-final against New Zealand. Photograph: Lakruwan Wanniarachchi/AFP/Getty Images

Upul Tharanga, the Sri Lanka batsman who struck an unbeaten century in their crushing World Cup quarter-final defeat of England, is expected to face an International Cricket Council inquiry after reportedly failing a drugs test during the World Cup.

Neither Sri Lanka Cricket nor the ICC would confirm persistent reports that Tharanga has tested positive for Prednisolone, which is a banned substance under the World Anti-Doping Agency code.

Tharanga is expected to explain that the substance was included in a treatment provided by an alternative medical practitioner who has been consulted in the past by leading Sri Lankan and Indian players.

Prednisolone is a drug used in a wide range of inflammatory and auto-immune conditions such as asthma. The Sunday Observer in Colombo has reported that Tharanga suffers from asthma, although recently he has also been treated for a knee injury.

Tharanga is said to have tested positive after a Sri Lanka match against New Zealand. The sides met twice, once at the group stage and again in the semi-final in Colombo.

Along with Tillakaratne Dilshan, he flayed England in the World Cup quarter-final in Colombo. Both batsmen made unbeaten centuries as Sri Lanka won by 10 wickets with more than 10 overs to spare. He is not in the Sri Lanka Test squad but would be expected to be chosen in their forthcoming squad for the one-day series that follows.

Nishantha Ranatunga, SLC's secretary, said: "Officially we know nothing about Tharanga's case. SLC has not received any complaints or reports about the use of the banned substance called Prednisolone from any organisation or agency."

Sri Lanka Cricket's interim committee are under siege as they face allegations of financial mismanagement during the World Cup which could ultimately lead them to seek a bail‑out from Indian cricket or their own government. They could now additionally face charges of failing to advise their players properly on the ICC's anti-drugs code.

The ICC finally signed up for a Wada‑approved drugs code last year after appeasing India's resistance to out-of-competition testing. At the time Haroon Lorgat, the ICC's chief executive, admitted that educating cricketers would be a prime challenge that respective boards would have to address.

"After a long and thorough process we now have a tough and practical set of rules that will support our zero-tolerance approach to doping in our great sport," Lorgat said. "Our next steps are to educate the relevant players and administrators so that they understand their responsibilities under the new rules."